29 



The analyses of both soils are here given, and the com- 

 parison shows the soil of the bad clover to be actually richer 

 in gypsum and common salt than the soil of the good clover ; 

 it, however, contains a little less magnesia, phosphate of lime, 

 and of silicate of potash. But by comparing the extract from 

 the table published by Professor Johnston, which contains the 

 number of pounds weight of inorganic substances required per 

 acre, with any of the ingredients in which the bad soil is defi- 

 cient, it will be found that there existed in the bad soil quite an 

 ample quantity of each of them. Take the quantity of phos- 

 phate of lime, the only one about which there can be a doubt, 

 the quantity in the analysis being 0.15 per cent., and therefore 

 of phosphoric acid 0.67 per cent. ; but a crop of red clover 

 requires of phosphoric acid only 15 lbs. weight per acre, and 

 an acre of this soil, six inches deep, weighed on the 5th of 

 April 2,766,060 lbs., and therefore contained 180 lbs. weight 

 of phosphoric acid. So that if the analysis had contained 

 only .001 per cent., it would have contained 27 lb.: nay, if 

 it had contained .0005, it would have contained nearly suffi- 

 cient, not only of phosphoric acid for the red clover, but also 

 sufficient chlorine, sulphuric acid, magnesia, and soda, for 

 either a crop of barley, rye grass, or wheat. This shows 

 that even the very minute analyses of soils given by Professor 

 Liebig are not sufficiently exact, although they exhibit the 

 thousandth part per cent, of the substance analysed; yet 

 before it can be asserted that any soil is deficient in alumina, 

 soda, sulphate, acid, or magnesia, chemists must, owing to 

 the small quantity of matter required in so large a mass, give 

 us less than one-half of the decimal parts afibrded in those 

 even by Professor Liebig. In fact, before it could have been 

 predicated whether the clover on this soil had failed for the 

 want of alumina, it must have been ascertained whether the 

 soil contained even .000011 per cent, of that earth. 



